Another optimised offshore jacket CP retrofit
At the very end of a previous CP retrofit delivery for the Southern Norwegian shelf, FORCE Technology Norway has been awarded another retrofit project from an operator in the Northern North sea for a large, ageing jacket structure.
This project was a bit more challenging than the previous, as depolarization of the structure was well in process and seawater depth was around 100 meters; this meant that current requirements were quite high to re-polarise the jacket back to protection criterion. Furthermore, many surrounding structures at the seabed led to several exclusion zones challenging positioning of the anode pods.
However, using our SeaCorr™ CP computer modelling software and thorough assessment of a range of CP inspection data, the retrofit design and solution was optimised in terms of extent of subsea intervention with positioning of the anode pods also including adequate tie-back cable dimensioning and other technical means for retrofit. To overcome the quite high retrofit current demand, we could still use our standard anode pods; we merely used Magnesium anodes with necessary mitigation to prevent over polarisation of the sleds risking hydrogen embrittlement and coating disbonding during service life.